Route destination field merged with nexthop attribute; splitting flowspec validation result out.

As there is either a nexthop or another destination specification
(or othing in case of ROAs and Flowspec), it may be merged together.
This code is somehow quirky and should be replaced in future by better
implementation of nexthop.

Also flowspec validation result has its own attribute now as it doesn't
have anything to do with route nexthop.

1 files changed, 45 insertions, 47 deletions

diff --git a/nest/rt-table.c b/nest/rt-table.c
index d98f33e4..539e04d0 100644
--- a/nest/rt-table.c
+++ b/nest/rt-table.c
@@ -699,7 +699,7 @@ rte_trace(struct channel *c, rte *e, int dir, char *msg)
 {
   log(L_TRACE "%s.%s %c %s %N %uL %uG %s",
       c->proto->name, c->name ?: "?", dir, msg, e->net->n.addr, e->src->private_id, e->src->global_id,
-      rta_dest_name(e->attrs->dest));
+      rta_dest_name(rte_dest(e)));
 }
 
 static inline void
@@ -1177,26 +1177,17 @@ rte_validate(rte *e)
     return 0;
   }
 
-  if (net_type_match(n->n.addr, NB_DEST) == !e->attrs->dest)
-  {
-    /* Exception for flowspec that failed validation */
-    if (net_is_flow(n->n.addr) && (e->attrs->dest == RTD_UNREACHABLE))
-      return 1;
-
-    log(L_WARN "Ignoring route %N with invalid dest %d received via %s",
-	n->n.addr, e->attrs->dest, e->sender->proto->name);
-    return 0;
-  }
-
   eattr *nhea = ea_find(e->attrs->eattrs, &ea_gen_nexthop);
-  if ((!nhea) != (e->attrs->dest != RTD_UNICAST))
+  int dest = nhea_dest(nhea);
+
+  if (net_type_match(n->n.addr, NB_DEST) == !dest)
   {
-    log(L_WARN "Ignoring route %N with destination %d and %snexthop received via %s",
-	n->n.addr, e->attrs->dest, (nhea ? "" : "no "), e->sender->proto->name);
+    log(L_WARN "Ignoring route %N with invalid dest %d received via %s",
+	n->n.addr, dest, e->sender->proto->name);
     return 0;
   }
 
-  if ((e->attrs->dest == RTD_UNICAST) &&
+  if ((dest == RTD_UNICAST) &&
       !nexthop_is_sorted((struct nexthop_adata *) nhea->u.ptr))
   {
     log(L_WARN "Ignoring unsorted multipath route %N received via %s",
@@ -2431,26 +2422,27 @@ rta_apply_hostentry(rta *a, struct hostentry_adata *head)
   u32 *labels = head->labels;
   u32 lnum = (u32 *) (head->ad.data + head->ad.length) - labels;
 
-  a->dest = he->dest;
-
   ea_set_attr_u32(&a->eattrs, &ea_gen_igp_metric, 0, he->igp_metric);
 
-  if (a->dest != RTD_UNICAST)
+  if (!he->src)
   {
-    /* No nexthop */
-    ea_unset_attr(&a->eattrs, 0, &ea_gen_nexthop);
+    ea_set_dest(&a->eattrs, 0, RTD_UNREACHABLE);
     return;
   }
 
-  if (!lnum && he->nexthop_linkable)
+  eattr *he_nh_ea = ea_find(he->src->eattrs, &ea_gen_nexthop);
+  ASSERT_DIE(he_nh_ea);
+
+  struct nexthop_adata *nhad = (struct nexthop_adata *) he_nh_ea->u.ptr;
+  int idest = nhea_dest(he_nh_ea);
+
+  if ((idest != RTD_UNICAST) ||
+      !lnum && he->nexthop_linkable)
   { /* Just link the nexthop chain, no label append happens. */
     ea_copy_attr(&a->eattrs, he->src->eattrs, &ea_gen_nexthop);
     return;
   }
 
-  eattr *he_nh_ea = ea_find(he->src->eattrs, &ea_gen_nexthop);
-  struct nexthop_adata *nhad = (struct nexthop_adata *) he_nh_ea->u.ptr;
-
   uint total_size = OFFSETOF(struct nexthop_adata, nh);
 
   NEXTHOP_WALK(nh, nhad)
@@ -2467,10 +2459,14 @@ rta_apply_hostentry(rta *a, struct hostentry_adata *head)
 
   if (total_size == OFFSETOF(struct nexthop_adata, nh))
   {
-    a->dest = RTD_UNREACHABLE;
     log(L_WARN "No valid nexthop remaining, setting route unreachable");
 
-    ea_unset_attr(&a->eattrs, 0, &ea_gen_nexthop);
+    struct nexthop_adata nha = {
+      .ad.length = NEXTHOP_DEST_SIZE,
+      .dest = RTD_UNREACHABLE,
+    };
+
+    ea_set_attr_data(&a->eattrs, &ea_gen_nexthop, 0, &nha.ad.data, nha.ad.length);
     return;
   }
 
@@ -2511,19 +2507,28 @@ rta_apply_hostentry(rta *a, struct hostentry_adata *head)
 static inline struct hostentry_adata *
 rta_next_hop_outdated(rta *a)
 {
+  /* First retrieve the hostentry */
   eattr *heea = ea_find(a->eattrs, &ea_gen_hostentry);
   if (!heea)
     return NULL;
 
   struct hostentry_adata *head = (struct hostentry_adata *) heea->u.ptr;
 
+  /* If no nexthop is present, we have to create one */
+  eattr *a_nh_ea = ea_find(a->eattrs, &ea_gen_nexthop);
+  if (!a_nh_ea)
+    return head;
+
+  struct nexthop_adata *nhad = (struct nexthop_adata *) a_nh_ea->u.ptr;
+
+  /* Shortcut for unresolvable hostentry */
   if (!head->he->src)
-    return (a->dest != RTD_UNREACHABLE) ? head : NULL;
+    return NEXTHOP_IS_REACHABLE(nhad) ? head : NULL;
 
+  /* Comparing our nexthop with the hostentry nexthop */
   eattr *he_nh_ea = ea_find(head->he->src->eattrs, &ea_gen_nexthop);
-  eattr *a_nh_ea = ea_find(a->eattrs, &ea_gen_nexthop);
 
-  return ((a->dest != head->he->dest) ||
+  return (
       (ea_get_int(a->eattrs, &ea_gen_igp_metric, IGP_METRIC_UNKNOWN) != head->he->igp_metric) ||
       (!head->he->nexthop_linkable) ||
       (!he_nh_ea != !a_nh_ea) ||
@@ -2682,16 +2687,16 @@ rt_flowspec_update_rte(rtable *tab, rte *r)
   const net_addr *n = r->net->n.addr;
   struct bgp_proto *p = (void *) r->src->proto;
   int valid = rt_flowspec_check(bc->base_table, tab, n, r->attrs, p->is_interior);
-  int dest = valid ? RTD_NONE : RTD_UNREACHABLE;
-
-  if (dest == r->attrs->dest)
+  int old = rt_get_flowspec_valid(r);
+  if (old == valid)
     return NULL;
 
   rta *a = alloca(RTA_MAX_SIZE);
   memcpy(a, r->attrs, rta_size(r->attrs));
-  a->dest = dest;
   a->cached = 0;
 
+  ea_set_attr_u32(&a->eattrs, &ea_gen_flowspec_valid, 0, valid);
+
   rte *new = sl_alloc(rte_slab);
   memcpy(new, r, sizeof(rte));
   new->attrs = rta_lookup(a);
@@ -3524,7 +3529,6 @@ rt_update_hostentry(rtable *tab, struct hostentry *he)
 
   /* Reset the hostentry */
   he->src = NULL;
-  he->dest = RTD_UNREACHABLE;
   he->nexthop_linkable = 0;
   he->igp_metric = 0;
 
@@ -3545,16 +3549,12 @@ rt_update_hostentry(rtable *tab, struct hostentry *he)
 	  goto done;
 	}
 
-      if (a->dest == RTD_UNICAST)
-	{
-	  eattr *ea = ea_find(a->eattrs, &ea_gen_nexthop);
-	  if (!ea)
-	    {
-	      log(L_WARN "No nexthop in unicast route");
-	      goto done;
-	    }
-	    
-	  NEXTHOP_WALK(nh, (struct nexthop_adata *) ea->u.ptr)
+      eattr *nhea = ea_find(a->eattrs, &ea_gen_nexthop);
+      ASSERT_DIE(nhea);
+      struct nexthop_adata *nhad = (void *) nhea->u.ptr;
+
+      if (NEXTHOP_IS_REACHABLE(nhad))
+	  NEXTHOP_WALK(nh, nhad)
 	    if (ipa_zero(nh->gw))
 	      {
 		if (if_local_addr(he->addr, nh->iface))
@@ -3567,10 +3567,8 @@ rt_update_hostentry(rtable *tab, struct hostentry *he)
 
 		direct++;
 	      }
-	}
 
       he->src = rta_clone(a);
-      he->dest = a->dest;
       he->nexthop_linkable = !direct;
       he->igp_metric = rt_get_igp_metric(e);
     }